Machine tool transmission and control mechanism



. March 3, 1942. J. B.'.ARI\"I1}ITAGEI ET-AL MACHINE TOOL TRANSMISSIONAND .CONQIROL MECHANISM I Fi led Marqh 18, 1959 4 Sheets-Sheet 1 vATTORNEY March 1942- J. B. ARMITAGE ETAL I 2 2 Y MACHINE TOOLTRANSMISSION AND CONTROL MECHANISM Filed March 18 1939 4 Sheets-Sheet 2YFZE ZI I 47 IN V E N-TO R 5 055px MB. AHMJ 2145.2; Janus; YI/IEAHKEH WMMM ATTORNEY MACHINE TOOL TRANSMISSION AND CONTROL MECHANISM FiIed'March18, 1939 4S heets-Sheet 3 INVENTORS DSEPH B. ABM] TAEE URHJN- 'I/I/LBARER ATTORNEY Maid: 3, 1942. J. a. ARM lTAGE ETAL I 2,275,241

MACHINE TOOL TRANSMISSION AND CONTROL MECHANISM Filed March 1s, 1 9 59 4She ets-Sheet'4 ATTORNEY.

Patented Mar. 3, 1942 MACHINE TOOL TRANSMISSION AND CONTROL MECHANISMJoseph B. Armitage, Wauwatosa, and Orrin W. Barker, Milwaukee, Wisassignors to Kearney & Trecker Corporation, West Allis, Wis., a cor- Qporation of Wisconsin Application March 18, 1939, Serial No. 262,756

29 Claim.

This invention relates, generally, to improvements in machine tools andmore particularly to improved power transmitting and controllingmechanism for effecting automatic control of the direction and rate ofoperation of a machine tool element.

A general object of this invention is to provide an improvedtransmission and control mechanism for actuating and automaticallycontrolling the movements of a machine tool element. 7

Another object of the invention is to provide improved machine toolcontrolling apparatus that may be adjusted readily to efiect any one ofseveral modes of automatic operation.

Another object is to provide improved reversing and rate changingcontrol mechanism for the table driving power transmission train of amillin machine.

Another object is to provide an improved reversing and rate changingcontrol mechanism for a machine tool table that may be adjusted readilyto provide for efiecting automatic reversal in the direction of movement01' the table into either feed rate or rapid traverse rate selectivelyat either end of its course of travel.

Another object is to provide a machine tool transmission and controlmechanism including feed rate and rapid'traverse rate driving trains andtable driving means adapted to be driven by either train, together withmeans operative to disengage the rapid traverse driving trainautomatically whenever the table driving means is disengaged from thetable.

Another object is to provide control apparatus for a machine tool tabledriving'mechanism including a feed train and a rapid traverse traintogether, with table reversing and disconnecting means adapted to bedriven by either train, the control means functioning automatically todismechanism for regulating the operation of the' hydraulic controlsystem 01' a machine tool.

According to this invention, a machine tool having a movable member isprovided with improved automatically actuated control mechengage therapid traverse train wherever the table reverser is moved todisconnecting position.

Another object is to provide rate and direction changing controlapparatus for a machine tool, so arranged that upon reversing movementthereof the rate is automatically reduced to iced rate as the reversingmechanism moves through neutral position, thereby preventing clashing ofthe clutches when the reverser is engaged for movement in the oppositedirection.

Another object is to provide reversing and rate changing controlmechanism for a machine tool, interlocked in such manner that the rapidtraverse rate driving mechanism can not become effective until after thereversingmechanism. for eflecting change in the direction of movement ofthe member at predetermined terminal points in its path of travel, themovement in reverse direction being eflected selectively either at feedrate or at rapid traverse rate an tomatically. The control system ispreferably hydraulically actuated, trip dogs being arranged to move areversing control valve which functions to energize a piston andcylinder reverser shifting mechanism. The reversing control valve isalso selectively operable to effect power movement of a rate changingvalve, the arrangement being such that the rate 01' movement may bechanged automatically subsequent to completion of a change in thedirection or movement. A single manually actuated selector valve may bepositioned to determine the rate at which reversal will occur at theends of the path of movement. or separately operated selector valves maybe provided for'each end of the path, whereby reversal into either ratemay be effected at either end of the path of travel. In a modification,a similar selective eflect is obtained by providing an auxiliary tripplunger adjacent to each reversing plunger to control the rate at whichreversal occurs, and alternatively the auxiliary plungers may bereplaced by selectively operable connecting linkages arranged to beactuated directly by the reversing control plungers to 'control the rateof reverse travel at either end of the course of movement oi! themovable member. The rapid traverse driving mechanism is preferably soarranged that it can be engaged only after the reversing mechanism hasbeen engaged to eflect movement in one or the other direction,

the arrangement being-such that the rapid traverse drive isautomatically disengaged whenever the reversing mechanism is disengaged,thereby obviating the risk of accidentally engaging the reversingclutches while they are operating at rapid traverse rate. I

The invention is exemplified herein by several embodiments illustrateddiagrammatically in connection with a general representation of atypical machine tool structure; however, it is to be understood thatthese particular embodiments are intended to be illustrative only andthat varalong the line 1-1 in Fig.

ious other structural forms, all within the range of equivalents of thefeatures defined in the subjoined claims, maybe employed in practicingthis invention in connection with any of various ma-.

,chine tools or similar apparatus.

The foregoing and other objects of this invention, which will becomemore fully apparent from the following detailed specification settingforth ing machine exemplifying a machine tool of the type in which thepresent invention may be incorporated to advantage, parts of the machineframe having been broken away to better show some of the controlmechanism;

Fig. 2 is an enlarged detailed view of one of the control plungers,taken largely in vertical section along the line 2-2 in Fig. 1;

Fig. 3 is a schematic or diagrammatic view of the hydraulic controlsystem associated with the machine shown in Fig. 1, fragments of thevalve mechanism being shown in vertical section;

Fig. 4 is a schematic view, generally similar to Fig. 3, but showing ahydraulic control'system incorporating a modification of the invention;

Fig. 5 is a schematic diagram of another control system generallysimilar to that shown in Fig. 4 but embodying still another modificationof the invention;

Fig. 6 is a fragmentary view largely in vertical section, of tripmechanism generally similar to that shown in Figs. 1 and 3 but embodyinga further modification of the invention;

Fig. '1 is a detailed view of part of the trip mechanism taken'generallyin vertical section Fig. 8 is a detailed view of another part of thetrip mechanism taken generally in vertical section along the line 8-8 inFig. 6.

The particular machine tool illustrated generally in Fig. l of thedrawings as exemplifying apparatus of the class adapted to be controlledin accordance with the principles of the present invention, is a millingmachine of the bed type generally similar in structure to the machine.

shown and described in detail in U. 8. Patent No. 2,077,434, issuedApril 20, 1937, and in U. 8. Patent No. 2,118,357, issued May 24, 1938.Referring more specifically to Fig. 1, the milling machine structurethere shown comprises essentially a hollow bed or base 50 thatconstitutes the main frame or foundation of the machine and 7 forms ahousing for the driving mechanism and the controlling apparatus. On itsupper rear surface, the base I0 supports a pair of rigidly mounted,spaced uprights II and I2 constituting together an upstanding columnstructure that supports for bodily movement a rotatable horizontallydisposed tool carrying spindle It.

To provide for adjustment of the position of a cutting tool carried bythe spindle i3 horizontally or vertically, the spindle is rotatablymounted in an axially movable quill i4 that is slidably mounted forendwise adjustment within a spindle block or carrier it which is, inturn, slidably mounted for vertical movement between the uprights H andi2 constituting the column structure, the arrangement being such thatthe cutter may be moved to any position in a vertical axial plane withinthe limits of the machine. Both vertical and horizontal adjustment ofthe spindle I! may be effected by means of screw and nut mechanisms, asshown in the previously mentioned patents, or by any other well knownadjusting means, suitable locking mechanisms being provided for clampingboth the spindle block I! and the quill l4 in the adjusted position. Thespindle block i5 likewise serves to support the usual pair of overarmsl6 that are slidably mounted in the block above the quill I4 in wellknown manner.-

Power for rotating the spindle I3 to drive a' cutting tool carriedthereby may be derived from a motor (not shown) ordinarily mountedwithin the hollow base I0, as described in the previously mentionedpatents, and operatively connected by means of speed changin'ggearing toeffect rotation of the spindle at a selected speed, in well knownmanner.

On the upper surface of the bed ill in front of the uprights II and i2constituting the column structure, is slidably mounted a reciprocatingwork-supporting table 20 guided for horizontal movement along the bed ina path transverse to the axis of the tool spindle l3 and in position tomove a workpiece supported thereon in cooperatgig relationship with atool carried by the spin- Power for reciprocating the table 20 islikewise derived from the motor in the base of the machine, in themanner described in the previously mentioned patents, and may betransmitted to ,the table for moving it at a selected one of a pluralityof feed rates by r'neans of a transmission mechanism including a feedscrew driven by a feed rate changer 2|. For moving the- -of the machineas shown in Fig. 1 and arranged for movement in two planes. When thelever 24 is moved either to the right or to the left from the centralneutral position shown in the drawings, the work-table 20 is caused tomove in the corresponding direction, the arrangement being such thatwhen the lever is moved inward toward the machine, movement of the tablewill occur at feed rate, while if the lever is moved outward or awayfrom the machine. the movement will occur at rapid traverse rate, theoperation being in accordance with the inventions set forth and claimedin the previously mentioned patents. Likewise, automatic change in therate of movement of the table may be effected by means of trip dogscarried by the table 20 and acting upon a vertically movable trip post25, while the movement of the table may be stopped by means of stop dogsarranged to engage the arms of s. rotatable trippin sleeve 28, as fullyexplained in the patents.

Referring now to the control apparatus shown shoe fixed on ahorizontally disposed rapid traverae control valve rod 2!. The rod 29 isfurther ferred to.

lower position as previously explained and the rapid traverse valve rod23 is moved to the right to feed position.

The previously mentioned sidewise movement of the lever 24 also affectsturning movement of the tripping sleeve 26, the pin 32 pivotally sup-'porting the leverbeing flxed in a bracket carried by and efl'ectingconnection with a rotatable sleeve 34 which incloses the control rod 3|and is arranged to be turned by sidewise movement of the lever'24. Asshown, the sleeve ,34 is provided at its inner end with an eccentric pin36 which engages a slot in a shoe carried by a reright, and when theplunger 43 is depressed the valve plunger is moved to the left.

Pressure fluid for actuating the automatic reversing mechanism isderived from a pump 63 which withdraws fluid from a sump 6| through aconduit 62 and forces it under pressure through a conduit 63 and aconduit 64 to a port 66 in the reversing valve casing 64. fluid flowsthrough a groove 66 in the reversing valve plunger 63 to a port 61 inthecasing which communicates with a conduit 63 leading to a port 63 in avalve casing 13 associated with the rapid traverse valve plunger 23, andthence through a conduit 1| and a conduit 12 to a low pressure reliefvalve 13 from which the pressure liquid may escape, preferably into thelubricating system of the machine, the pressure within the versingshifter rod 36. Furthermore, the shifter rod 36 is provided with a sloteng ing an arm 31 carried on the lower end of the tripping sleeve 26,the arrangement being such that when the lever 24 is moved from side toside, the shifter rod 36 is moved axially to effect reversal and thesleeve 26 is turned about its axis.

The shifting rod 36 carries a reversing and disconnecting shifting fork43 which engages a reversing clutch gear 4| and is operative to move theclutch gear from the neutral position shown into engagement with eitherone of two complementary driving clutch gears 42 and 43, the arrangementconstituting a reversing and disconnecting mechanism. When the clutchgear 4| is engaged with one of the driving clutch gears it will bedriven thereby and will turn an intermeshing sleeve gear 44 thatslidably receives and drives a table screw 46 in well known manner toeffect movement of the table 23 in the one or the other direction.Engagement of the complementary reversing clutch gears may be effectedmanually by movement of the hand lever 24 to the right or to the leftfrom its central neutral position to effect corresponding movement ofthe-- means of stop dogs operative to engage the tripping sleeve 26 toturn it in manner to niove the clutch gear 4| to its neutral position,as more fully explained in the To provide for effecting automaticreversal in the direction of movement of the table 23, a pair ofreversing trip posts or plungers 41 and 43 are disposed respectively atopposite sides of thetrip sleeve 26, in positions to be engaged anddepressed by reversing trip dogs such as the dog 49, carried by thetable, the arrangement being such that hydraulic pressure may thereby beapplied to the one or theother side of a reversing piston 63 fixed onone end of the reversing shifter rod 36, as may be required to eflectthe reversal. As shown in Fig. 3, the reversing plungers 41 and 43 arespring urged to-neutral or central position and act respectively uponthe ends of a medially pivoted lever 6|. The lever 6| is provided with adepending arm 62 the lower end of which engages a slot in a reversingvalve plunger 63 fitted in a reversing valve casing 64, the arrangementI being such that when the trip plunger 41 is depatents previouslyrepressed, the valve plunger 63 is moved to the pump 63 and theconnected pressure system being determined by the setting 01' the reliefvalve 13. From the pump pressure conduit 63, another passageway leads tothe reversing valve casing 64 through a conduit 16, a port 16 of aspindle control valve 11, a groove 13 of an associated valve plunger 13,and a conduit 33 leading to a pressure port 3| in the reverser valvecasing 64.

When one of the reversing trip plungers 41 or 43 is depressed by areversing dog. pressure is applied to the appropriate side of thereversing piston 63 toeflect reversal. For example, if the table 23 ismoving from right to left, as shown in Fig. 1, and the reversing dog 43engages the reversing plunger 43, at the end of the course of travel ofthe table, the plunger 43 will be depressed and the reversing valveplunger 63 will be moved to the left. This results in bringing a narrowgroove 32 in the plunger into communication with the pressure port 3|,whereupon the pressure fluid flows longitudinally through a channel 33in the plunger 63 to the right end of the valve casing 64, therebyexerting force on the right end of the plunger in manner to move it tothe left quickly to eflect the reversing operaits neutral position alsocauses the groove 66 therein to move out of communication with the port66, thereby preventing the escape of pressure fluid through it into theport 61 and the conduit 63 leading to the low pressure relief valve.This causes the pressure in the pump and in the conduit 33 to build-upto.a high pressure determined by the setting of a high pressure reliefvalve 34 connected to the pump conduit 63 and discharging into the lowpressure conduit 12.

Further movement of the valve plunger 63 to the left brings a groove 36in the plunger into communication with the pressure port 3| and permitsthe high pressure fluid to flow into a port 36 that is connected by aconduit 31 to the leftend of a cylinder 33 within which the reversingpiston 63 is fitted for sliding movement. The high pressure in the leftend of the cylinder 33 then causes the piston 63 to move quickly to theright thereby engaging the reversing clutch gear 4| with the clutch gear43 in manner to effect movement of the table to the right.

Since under some circumstances it is desired that the movement in theOpposite direction be caused to take place at rapid traverse rate, asset forth in the previously mentioned patents, the reversing cylinder 33is provided with a medial port 33 which is uncovered when the reversingpiston 63 approaches the end of its stroke in either direction, therebyestablishing communication with a conduit 33 leading to an actuatingcylinder 3| associated with and formed in one end From the .port 66, the

i from the low pressure supply of the rate changing or rapid traversevalve casing 10. The pressure fluid escaping into the cylinder II thenacts upon a piston 32 therein, which is carried by the rapid traversevalve plunger 20,

and functions in manner to move the plunger to leads to an annularchamber 3! formed circumferentlally of a stationary plug 33 fitted.within the sleeve 93 and constituting part ofthe left end of thecylinder '9I. After the piston "on the rapid traverse valve plunger 23has been moved to the left to the full extent, the pressure within thecylinder BI builds up to the high pressure determined by the setting ofthe high pressure relief valve 34 and exerts sufficient force upon theright end of the sleeve 93 to overcome the force exerted by the lowpressure fluid upon the left end thereof. This results in moving thesleeve 93 to the left to a position in which it uncovers and establishescommunication between a port 91 and a port 88 diametrically disposed inthe wall of the cylinder GI, thereby establishing communication betweena conduit 88 leading to the left end of the reversing valve casing 54and a conduit no leading. to the right end of the casing 54 forequalizing the pressures onthe ends of the reversing valve plunger 53 topermit it to be returned to its neutral position by the self-center'-ing spring urged tripping plungers l1 and it With the reversing valveincentral position and the rapid traverse control valve plunger 28 in theleft position as a result of a reversing action, a low pressure fluidcircuit is established through the conduits 63 and 84, the port 85.

groove 68, port 81 and conduit 68 to the port 89' in the rapid traversevalve casing, and thence by way of a groove IBI in. the rapid traverseplunger 28, a port Hi2, and a conduit M8 to a port I84 in a valve casingI05 encircling the reverse shifter rod 36. With the reversing mechanismshifted to the right as previously described, the port 896 communicateswith a groove I06 in the shifter rod 36 which is in register with aportI85. From the port I 09 a conduit IIB leads to the fluid pressureactuated rapid traverse clutch 22, which may be generally similar instructure to the clutch mechanism more fully described and claimed inthe co-pending application of Jdseph B. Armi-.

tage, serial No. 86,559, filed June 22, 1938 and entitled Machine tool,that issued September 24:, 1940 as Patent No. 2,215,684the arrangementbeing such that. when pressure is applied to the clutch mechanism .22, amultiple plate friction clutch is engaged to operate the table 2|! atrapid" traverse rate in the direction determined by the position of thereversing clutch gear CI.

Since it is sometimes desirable that the cutter spindle be stoppedwhenever the table is operated in reverse direction at rapidtraverserate,.

in order to avoid marring the workpiece by the rotating cutter, therapid traverse valve is provided with additional ports which function tostop the spindle automatically simultaneously with engagement of therapid traverse drive. As shown in Fig. 8, fluid pressure for controllingthe I". t or spindle driving clutch is derived conduit I3 throughtoaport iitinthespina conduit H8 leading die controlvalve ll.

:. thence by way of a various valves in the positions shown, 'lowpressure from the through them into the conduit I2I of a spindle stopselector valve. As shown,

the port I23 communicates through a groove III in a selector valveplunger- I23 with a port I which is connected by means of a conduit IIIwith a port I13 in mg". The port Ill is, in turn, connected by means ofa groove III in the rapid traverse valve plunger 20 with a port I23 thatcommunicates with a conduit I23 leading to the main clutch controlmechanism, as more fully described in the previously mentioned patents.with the uidat I23 and operates to maintain the main clutch inengagement to drive the spindle. Whenthe rapid traverse valve plunger 33is moved to the .left to engage the rapid traverse drive, thegroove I2!is moved out of communication with the port I23 thereby cutting of! thefluid pressure supply to the conduit I23 and causing the main clutch tobe diseneased.

In the event that it is desired to effect automatic reversal withoutstopping the spindle, the selector valve plunger I23 may be moved to theleft by manipulating a control lever I3l, shown on the front of themachine in Fig. 1. This causes the groove I22 in the plunger I23 to moveinto register with another port I32 into which the pressure fluid flowsfrom the port I20 and conduit I33 to a port I34 in the rapid traversevalve casing 10. When the rapid traverse valve plunger ll is moved tothe left to rapid traverse position, the groove I2? therein registerswith the port I" and provides cylinder 83 in manner with the spindlecontrol "the an altemative source of pressure communicating with theport E28 and the clutch controlling conduit I28 thereby functioning toretainthe main clutch in engaged position.

If it is desired to disengage the main clutch manually, the clutchcontrolling valve plunger I9 may be moved to the left by means of amanually actuated clutch controlling lever I36, shown mounted on thefront of the machine in Fig. i

just below the reversing lever 24. With the plunger It in the left' orstop position, the groove II! is moved out of communication with the-pressure port H8 and into communication with an exhaust port I31,thereby cutting of! the pressure to the clutch controlling conduit E29and causing the .clutch to be moved to disengaged position. Movement ofthe plunger 19 to the left position likewise moves the groove 18 out ofregister with the high pressure port 18, thereby cutting off the supplyof actuating the automatic reversing mechanism and preventing accidentalit be moved manually to a position in which a reversing dog engages areversing plunger when the spindle is not running.

Automatic reversal in the direction of movement of the table 26 when itis moving from left to right is effected in corresponding manner byengagement of a reversing dog with the left hand reversing plunger 4?.This results in moving the reversing valve plunger 53 to the right andthereby admitting high pressure fluid from the port @I through a grooveI33, a port I33 and a conduit ill to-the right end of the reversing tomove the piston 53 and shifting. rod 88 to the left to engage the therapid traverse valve cassupply conduit 13 flows high pressure fluid forreversal of the table should plunger to be moved downward also.

of the reversing valve is in this instance similar to that previouslyexplained although in the opposite direction, the rapid traverse valveplunger 25 being moved to rapid traverse position after the reversingaction has taken place, and the reversing valve then being neutralizedby movement of the neutralizing sleeve 55 to the left as previouslyexplained.

According to an important feature of this invention, the controlmechanism may be adjusted to effect reversal at feed rate instead of atrapid traverse rate. For this purpose there ar provided a pair ofauxiliary or supplemental tripping plungers I and I42 arrangedrespectivelyadjacent to and at the left and rightof the correspondingreversing plungers 41 and 45, as shown, the auxiliary plungersfunctioning when depressed to render the rapid traverse valvenonresponsive to a reversing operation. The two auxiliary plungers I andI42 are interconnected for simultaneous movement in the same direction,the plungers being provided near their lower ends with slots I45 andI44, respectively, which are engaged by the ends of lever arms I45 andI44, as best shown in Fig. 2. The lever arms I45 and I45 are carried onthe respective ends of an interconnecting rocking shaft I41, thearrangement being such that when either plunger is depressed it actsupon the corresponding arm to turn the rocking shaft, therebycausing theother For retaining the plungers normally in raised position, theplunger I42 is provided with a compression spring I48 that retains it inits upper-position and, by means of the interconnecting rocking shaftI41, retains the plunger I in the upper position likewise.

When it is desired to effect automatic reversal in the direction oftable movement at feed rate instead of at rapid traverse rate when areversing plunger is depressed, the corresponding auxiliary plunger isdepressed simultaneously with downward movement of the reversing plungerthereby actuating interlocking mechanism rendering the rate changingvalve nonresponsive. For this purpose a special, combined reversing dog,such as the dog II shown in Fig. 1 may be provided, the combined dogpresenting two inclined surfaces I52 and I55 disposed, respectively, toengage the reversing plunger 41 and the auxiliary plunger I fordepressing both of them simultaneously. Referring now to Fig. 3, whenthe auxiliary plunger I, for example, is depressed by the slopingsurface I 52 of the dog I5I, it establishes a hydraulic connection whichprevents movement of the rapid traverse valve plunger 25 to the rapidtraverse position when the reversing valve is actuated by thecorresponding reversing plunger '41.

As shown, the auxiliary plunger I4I constitutes a valve plungerpresenting a cannelure I55 and sliding within a cooperating valve casingI54.

When the auxiliary plunger-HI is moved downward to cause the reversal tooccur at feed rate,

fluid at high pressure flows from the high pressure conduit 85 through aport I51 in the valve casing I45, which is then connected by the can- Inelure I55 with a port I54 leading into a conduit I55. The conduit I55leads through the stationary plug 54 in the left end of the rapidtraverse "=-'cyllnder '5I and permits the high pressure fluid to exertforce on the left face of the piston 52 on the rapid traverse valve rod25 to render it inoperative. Since the area of the left face of thepiston 52 is greater than the effective area of the right facethereof,the piston will be prevented from moving to the left under the influence5 of pressure admitted from the reversing cylinder through the conduit50, thereby retaining the valve plunger 25 in feed position andpreventing engagement of the. rapid traverse clutch 22. However, theneutralizing action of the sleeve 55 will not be interfered with, as itwill be moved to the left by the high pressure fluid admitted throughthe conduit 55 into the right end of the cylinder 5I, since the left endof the annular chamber 55 is connected at all times to the low pressureconduit 54., thereby neutralizing the reversing valve plunger 55, aspreviously explained.

For eflecting reversal of the table at feed rate in the other direction,a dog similar to but ar-' ranged oppositely from the dog I5I may be pro-44 and the corresponding auxiliary plunger I42 simultaneously. In thiscase the plunger I H is also moved downward by the connecting linkage asbefore explained, the cannelure I55 establishing communication from thepressure port I51 to the port I55 and the conduit I55 leading to theleft end of the rapid traverse actuating cylinder 5I, to restrain therapid traverse valve plunger connected by the cannelure I55 with anexhaust,

port I45, whereupon fluid in the left end of the rapid traverse cylinder5I may be forced out through the conduit I55, the port I58, thecannelure I55 and escape through the exhaust port I when the piston 52is moved to the left in 5 moving the rapid traverse valve plunger 25 to-rapid traverse position.

As a modification of this invention, the 'auxiliary plungers HI and I42may be dispensed with and interlocking means provided for actuating theauxiliary control valve selectively directly from the respectivereversing plungers 41 and 44. As shown in Figs. 6, 1 and 8, this may beaccomplished by providing a valve plunger I5I corresponding generally tothe auxiliary plunger I4I shown in Fig. 3. and functioning in the likemanner. As shown in Fig. 6, the valve plunger I 4| is urged to itsupward position by a spring I42 and is provided at its upper end with aslot I 45 that is engaged by the outer end of an arm I64 fixed on arocking shaft I55, as best shown in Fig. 7. The rocking shaft I45carries a pair of arms I44 and I41 which are slidably keyed thereon andarranged to be moved longitudinally thereaiong into or out of posit-ionbeneath the cated in Fig. 8.

arm is depressed by the plunger acting upon the end of the lever II, asindicated in Fig. 8, and vcauses the rocking shaft I44 to turn, therebymoving the valve plunger l4l downward for establishing a connection fromthe pressure port vided for depressing the right reversing plungerrespective reversing plungers 41 and 44, as indi- When one of the arms.for example the arm I41 is moved into position beneath its correconduit208 control valve casing I88 which is connectedby I" to the conduit I88to prevent operation of the rapid traverse valve as previouslyexplained. For moving the arms I88 and I81 into and out of register withthe corresponding reversing piungers,-two shifting levers I10 (only oneof which is shown) may be provided on the front of the machine, eachbeing connected with an arm III which engages a slot H2 in thecorresponding tripping arm, whereby the tripping arm may be moved alongthe rocking shaft I88 by turning the lever I10 from one to the otherposition.

Although hydraulic means have been shown for preventing movement of therapid traverse valve when it is desired to effect reversal at feed rate,it is to be understood that other meansmay beemployed to achieve thesame result, for instance mechanical means may be used to preventmovement of the rapid traverse valve, as might be accomplished byproviding on the table a special dog which would positively preventupward movement of the tripping post 28 at the time of reversal.

The embodiment of the invention shown diagrammatically in Fig. 4 is ahydraulic control system generally similar in operation to that shown inFig. 3, but more particularly adapted for use in a milling machine ofthe knee and column type, as disclosed in the previously mentionedPatent No. 2,215,684. In this embodiment, the automatic reversingaction-is effected in manner similar to that previously explained bymeans of reversing dogs arranged to engaBe one or the other of a pair ofreversing plungers Ill and I'll that are interconnected by means of amedially pivoted link I'I8 for simultaneous movement in oppositedirections respectively. As shown, the plunger I'll is connected bymeans of a medially pivoted link I80 to actuate a vertically disposedreversing valve plunger I88 withi in its cooperating valve casing I84, aspring I88 being provided on the valve plunger to retain it and theinterconnected reversing plungers I11 and I" normally in central orneutral position. The arrangement and operatiomof the plungers I11 andI18 and the reversing valve plunger I88 is generally similar to that ofthe reversing valve and actuating plungers shown and more fullydescribed in the previously mentioned Patent No. 2,215,684.

Fluid pressure for actuating the control apparatus is, in this instance,derived from a pump I88 which withdraws fluid from a sump I88 through aconduit I80 and forces it under pressure into a conduit I8I leading to aport I82 in a spindle clutch controlling valve casing I88. From the portI82 the pressure fluid passes through a groove I84 in a rotary valveplug or rotor I88 fitted within the casing I88, and thence to a port I88in the casing connected by a conduit I81 to a port I88 in the reversingvalve oasing I84. with the reversing valve plunger I88 in the neutralposition as shown, a groove I88 therein effects communication betweenthe port I88 and a port 208 which is connected by a conduit 20I to aport 202 in a rapid traverse'valve casing 208. From the port 202 anotherconduit 204 leads to a low pressure relief valve 288 through which thepressure iluid may escape, preferably into: the lubricating system ofthe machine.

l'tom the low pressure conduit 204 another leads. to a port 201. in thespindle is then connected by a groove 2I2 in a cooperating rapidtraverse valve plunger 2I8 with a port 2I4. From the port 2I4, the lowpressure fluid flows through a conduit 2I8 into a flexible conduit 2 I8which leads to a relay valve (not shown) arranged to control theoperation of the main clutch of the machine, as fully set forth andclaimed in the previously mentioned Patent No. 2,215,884. Manual controlof the main clutch may be eflected by means ofa control lever 2|8mounted on the front of the machine and operatively connected byintermeshing gearing 2I8 to rota'te the spindle controlling valve rotorI88 within the casing I88 in such manner that the fluid pressure sourcemaybe connected to or disconnected from the conduit 2I8 leading to theclutch actuating relay by sidewise movement of the lever 2I8 from oneposition to another as fully explained in the patent.

If now, one of the reversing plungers, for example the plunger IIl, isdepresed by a reversing a groove 208 in the valve rotor I88 with a portdog, the reversing valve plunger I88 will, in this instance, be movedupward thereby moving a narrow groove 228 therein into communicationwith a pressure port 224 which is connected by a conduit 228 with thepressure conduit I81. The pressure liquid from the port 224 then flowsthrough a conduit 228 extending longitudinally of the valve plunger I88to the lower end of the valve casing I84, the pressure exerting forceupon the lower end of the plunger to move it quickly to itsupperposition. Upward movement of the reversing valve plunger I88 alsomoves the groove I88 out of communication with the port I88 therebypreventing the flow of pressure fluid from the pump I88 to the lowpressure relief valve 208. This results in the pressure being built-upin the conduits I8I and I81 to a high pressure that is determined by thesetting of a high pressure relief valve 22I which is con-- and connectsit with a port.228 from which a conduit 228 leads to the right end of areversing cylinder 280. The high pressure fluid admitted to the rightend of the cylinder 280 acts upon a reversing piston 28I therein inmanner to move it to the left to shift the reversing clutch foreflecting movement of the machine table in the opposite direction, asfully explained in the. previously mentioned Patent No. 2.215.684.

After the reversing clutch has been engaged and the piston 28Iapproaches 'the left end of the cylinder 280, it uncovers a port 288 atthe middle of thecylinder through which the high {pressure liquid flowsinto a conduit 284 leading to a port 288 in the reversing valve casingI84.

From the port 288, a conduit 288 leads to a port 281 in a selector valvecasing 288 associated with the spindle controlling valve mechanism andslidably receiving a valve plunger 288. The selector valve plunger 288functions to determine the rate at which automatic reversal will occur,and with the plunger in the position shown, reversal of the machinetable will occur at feed rate. As shown, a cannelure 240 in the plunger288 eflects a connection from the port 281 to a a,a7s,a41 7 t that it isat desired to stop the spindle autoport 24I from which a conduit 242leads to branch conduits 243 and 244 respectively connected toauxiliary-neutralizing valves 245 and 246. The high pressure liquid inthe -branch con-- duits 243 and 244 acts upon spring pressedpismatically upon reversal, a control knob 262 associated with thespindle control lever 2" is withdrawn and moved angularly to positionthe I98 to the port 200 which permits escape of the high pressure fluidthrough the low pressure relief valve 205 and re-establishes theconditions which obtained in the system prior to the beginning of thereversing operation.

To effect reversal from movement in the opposite direction, thereversing plunger I18 may be depressed by a reversing dog thereby movingthe reversing valve plunger I83 downward and establishing communicationfrom the pressure port 224 through a groove 250 in the valve plunger toa port 25] which is connected by a conduit '252 with the left end of thereversing cylinder 230. When the reversing piston 23I is then forced tothe right by the pressure in the left end of the cylinder, the reversingclutch is shifted to the opposite position and the port 233 is againuncovered to permit flow of the high pressure fluid through the conduit234, the port- 235 and the conduit 238 to the port 231 of the selectorvalve 238.

If in this instance it is desired to effect the reversal at the rapidtraverse rate, the selector valve 233 is moved to the left by pullingoutward on a selector actuating knob 253 thereby causing the cannelure240 to establish communication from the pressure port 231 to a port 254vfrom which a conduit 255 leads to a port 256 in the casing 203 of therapid traverse valve. The pressure admitted through the port 256 thenacts upon the lower face of a piston 251 on the rapid traverse valveplunger 2I3 in manner to move it to its upper or rapid traverseposition. When the piston 251 is moved to its upper position, ituncovers a port 258 in the valve casing through which fluid flows intothe conduit 241 leading to the upper end of the reversing valve casingI64, and at the same time a port 253 in, the rapid traverse valveplunger 2I3 moves into communication with the port 256 and therebyestablishes connection through a longitudinal passageway 260 in theplunger 2I3 with a port 26I at the lower end of the casing 203 whichcommunicates with the conduit 248 leading to the lower end of thereversing valve casing I84. This results in prearranging. part of aneutralizing circuit for equalizing the pressure on the ends of thereversing valve plunger to permit it to return to its neutral position,the valves 245 and 246 functioning meanwhile to prevent the neutralizingaction until after the rapid traverse valve has moved to its upperposition.

- Withthe rapid traverse valve plunger 2| 3 in the upper position, thegroove 2I2 therein is moved out of communication with the port 2I I,thereby disconnecting the pressure source'irom the port 2I4 and theconduit 2I5 leading to the pilot valve of the main clutch, to cause theclutch to be disengaged for stopping the cutter spindle during thereversing movement. In the event valve rotor I35, as explained in thepreviously mentioned patent No. 2,215,684, for establishing connectionfrom the low pressure port 201 to a port 263-from which the pressurefluid flows through an alternative conduit 264 to a port 265 which isthen connected by the groove 2I2 with the port 2I4 for maintainingpressure in the conduit 2I5 to retain the main clutch in engagement.

ton 23I. With the piston 23I in its extreme right position, a groove 213in a cooperating valve plunger 214 connected to the piston, is inregister with the port 210 and is connected by means of a longitudinalpassageway 215 through the plunger to a groove 216 which communicateswith a port 211 that is connected by a conduit 218 to a coupling member219 constituting a rotatable connection with a rapid traverse clutchmechanism 280 generally similar to the clutch mechanism 22 shown in Fig.3, the arrangement being such that when pressure is applied to therotary coupling member 213, the clutch mechanism is engaged to drive themachine table at rapid traverse rate in the direction determined by theposition of the reversing piston 23I.

In order to prevent operation of the rapid traverse drive when thereversing clutch is in the neutral or disengaged position correspondingto the intermediate position of the piston 23L as shown, the valveplunger 214 is arranged to close the pressure port 210. when in thisposition, and to connect the rapid traverse port 211 with an exhaustport 28I in manner to relieve the pressure in the clutch mechanism andpermit it to move to disengaged position. This interlocking arrangementprevents unnecessary operation of table in the opposite direction.

In the embodiment of the invention shown in Fig. 4, the selector valve238 provides for effecting reversal of the table at either-rapidtraverse rate or feed rate, the rate of reversal being the same at bothends of the course of travel of the table and depending upon theposition of the selector valve. According to the modification of theinvention shown diagrammatically in Fig. 5, the single selector valve239 of Fig. 4 is replaced by two selector valves arranged to provide forautomatic reversal of the table selectively at' either rate-at eitherend of its course of travel.

Referring now to the control circuit shown diagrammatically in Fig. 5,if the table is assumed to be moving from left to right, the reversingtrip plunger I11 will be depressed when enlishing a connection from thepressure port 224 to the port 228 which is connected to the conduit 229,as previously explained. The conduit 229 leads to the right end of areversing cylinder 290, corresponding generally to the reversingcylinder 280 shown in Fig. 4, but longer than it and fitted with arelatively long reversing piston 29I which is connected to actuate thereversing clutch as previously explained. When the piston 2 9| is forcedto the left by the pressure fluid in the right end of the cylinder, itengages the clutch to eflect movement of the table to the left, anduncovers one of two ports in the midportion of the cylinder wall, inthis case a port 298 leading into a conduit 294. The conduit 294 leadsto a port 295 in the casing of a right end reversing selector valve 296fitted with a cooperating plunger 291 having a cannelure 298 that, inthe right hand position of the valve shown, connects the port 296 to aport 299 from which a short passageway 800 leads to an annular' port 80Iin the casing of a left end reversing selector valve 802. As shown, theport SM is directly connected to, a conduit 808 leading to the port 236in the reversing valve casing I84 which is directly connected by meansof a conduit 804 with the port 256 in the rapid traverse valve casing208, the arrangement being such that the high pressure fluid flowingthrough the reversing cylinder 290 is admitted through the port 256 toexert pressure on the lower face of the rapid traverse valve piston 261for moving. it upward to rapid traverse position, with the result thatthe rapid traverse clutch is engaged and the reversing valve plunger I88is neutralized, as previously explained.

If now it is assumed that the table in moving from right to left engagesthe reversing plunger I18 (Fig. 4) thereby moving the reversing valveplunger I88 downward as previously explained, the pressure port 224isthen connected to the port 25I from which the conduit 262 leads to theleft end of the reversing cylinder 290. Upon the reversing piston 29Ibeing moved to the right by the pressure in'reversing the direction ofmovement of the table, it uncovers the other of the two ports in thecylinder wall, in this case a port 301 which is connected by a conduit808 to a port 809 in the casing of the left end selector valve 302. Aselector valve plunger 8II within the valve casing 802 is provided witha cannelure 8I2 which, when the valve is in the left position shown,effects communication between the port 809 and a port 8I8 that isconnected by a short conduit 8I4 with an annular port 8|! in the valvecasing 296. As shown, the port 8I5 is directly connected to a conduit8I1 which leads to a port 8I8 in the casing 208 of the rapid traversevalve at a position Just above the actuating piston 261 and beneath afloating neutralizing piston 820, the pressure acting downward upon thepiston 261 and rendering the rapid traverse valve inoperative. Theneutralizing piston 820 is slidably mounted upon the rapid traversevalve plunger 2 I8 within the upper part of the casing 208, and isnormally retained in its lower position in .contactwith the piston 261by means of a compression spring 82I. However, when pressure is admittedfrom the conduit 8" through the port 8I8 to the lower face of theneutralizing piston 820, the piston is moved upwards away from thepiston 261 against the resistance of the spring 82I to a position inwhich it uncovers a port 822- in the casing 268 which is connected by aconduit 828 to the upper end of the reversing valve casing I84. At thesame time, the neutralizing piston 820 uncovers a port 824 in the rapidtraverse valve plunger -2I8 that establishes communication through thelongitudinal passageway 260 in the plunger 2I8 with the port 26I at thelower end of the rapid traverse valve casing which is directly connectedby a conduit 826 with the lower end of the reversing valve casing I 84,thereby establishing communication between the upper and lower ends ofthe reversing valve casing to neutralize the reversing valve plunger I88as previously explained, but without moving the rapid traverse valveplunger 2 I 8.

' As shown, the selector valve plungers 281 and 8 are each provided withactuating knobs 821 and 828, respectively, by means of which the valvesmay be moved independently to either one of two positions, as determinedby spring actuated detent mechanisms 829 and 880. As previouslyexplained, with the selector valve plungera in the positions shown inFig. 5, reversal of the table from movement toward the right to movementtoward the left will occur at rapid traverse rate, whereas reversal ofthe tabl from movement toward the left to movement toward the right willoccur at feed rate. If now the valve plunger 291 is moved to its leftposition also, reversal will occur at feed rate at both ends of thecourse of travel, and conversely, if both of the plungers 291- and 8"are moved to their right positions, reversal will occur at rapidtraverse rate at both ends of the course of travel. Accordingly, withthis arrangement, it is apparent that reversal in the direction ofmovement of the table may be caused to occur'selectively at either rapidtraverse rate or feed rate at either end of its course of travel bysuitably manipulating the selector valve knobs 821 and 828.

From the foregoing description of typical control apparatus embodyingthe present invention to automatic reversal in the direction of movementof the element at selected rates.

Although the several illustrative embodiments and modifications of theinvention have been fully described for the purpose of setting forthvarious examples of operative embodying appa- J ratus, it is to beunderstood that the particular structures and control systems hereindescribed are intended to be illustrative only and that the variousinventive features may be incorporated in other structural forms withoutdeparting from the spirit and scope of the invention as deflned in thesubioined claims.

The principles of the invention having now been fully explained inconnection with the foregoing description of the embodying apparatus, wehereby claim as our invention:

1. In a machine tool, the combination with a movable support andtransmission mechanism for effecting movement of said support includingmeans shiftable for effecting alternative opposite directions ofmovement and for effecting alternative-feed or rapid traverse rates ofmovement, a first controller for efiecting change in direction ofmovement independently of change in rate, a second controller forefiecting change 1 direction, and control means selectively operable toeil'ect operation of, said rate changing controller in response tofunctioning of said direction changing controller, whereby movementafter reversal may be effected at either feed rate or rapid traverserate selectively.

2. In a machine tool, the combination oi a tool support and a worksupport, a transmission for effecting relative movement of said supportsincluding means for causing said relative movement to occur at feed-rateor at rapid traverse rate alternatively and in alternate directions, andcontrol mechanism for said transmission including a first manuallyoperable controller for selecting the direction of movementindependently of change in rate, a second controller manually operablefor selecting the rate of movement independently of change in direction,a dog controlled means capable of efiecting simultaneous change. in bothdirectionand rate, and selective control means operative to render saiddog controlled means incapable of effecting change in ratesimultaneously with change in direction.

3. In a machine tool having a tool support and a work support, thecombination with a transmission for effecting relative movement of saidsupportsincluding a feed rate train, a rapid traverse rate train, aselector shiftable to cause said relative movement to be effectedalternatively by the one or the other of said trains, and a shiftablereverser operative to effect change in the direction of said relativemovement, of control mechanism for said transmission including a firstmanually operable controller for operation of said reverserindependently or said selector, a

second manually operable controller for inde-,

pendent operation of said selector, a first dog operable control meansfor independently shifting said reverser and said selector, a second dogoperable control means for substantially simultaneous operation'of saidselector and said reverser, and control means selectively operable toprevent operation of said selector by said second dog operated controlmeans, whereby automatic reversal in the direction of said relativemovement may be efiected selectively by the one or the other of saidtrains.

4. In a machine tool having a tool support and a work support, thecombination with a transmission mechanism for eflecting relativemovement ofsaid-supports, including a feed rate train, a rapid traverserate train, a selector shiftable to connect the one or the other of saidtrains alternatively for effecting said relative movement, and areverser shiftable to efiect change in the direction of said relativemovement, of control apparatus for said transmission mechanism includingmeans responsive to said relative movement of said supports and capableof effecting simultaneous shifting of said reverser and said selector,and selectively actuata-ble control means capable of preventing shiftingof said seoperating said selector simultaneously with said reversingmechanism.

6. In a machine tool having a reciprocatory support, means forreciprocating said support at feed and rapid traverse ratesalternatively, means for controlling said reciprocating means includingmeans'to reverse said support and means to change the rate ofreciprocation of said support, pressure-fluid operated means responsiveto movement of said support and operative upon said reversing means to'eflect reversal in the direction of movement of said support, otherpressure-fluid operated means selectively responsive to operation orsaid reversing means and operative upon said rate changing means toeflect change from feed rate to rapid traverse rate, and

. control means for rendering said rate changing lector by said movementresponsive control apparatus. whereby said change in direction of saidrelative movement may be eiIected selectively to cause reverse movementat either feed rate or rapid traverse rate.

5. In a machine tool, the combination with a plurality of relativelymovable supports and power transmission and control mechanism foreflecting relative movement of said supports, including reversing andinterrupting mechanism and a selector shiftable to effect operationalfluid operated means responsive or non-responsive to said reversingmeans, whereby said support may be reversed into movement at feed rateor at rapid traverse rate selectively.

7. In a machine tool having a movable supporting member, the combinationwith power actuated means for moving said member, 01 a control systemfor said power actuated means comprising reversing mechanism" disposedto beactuated by said member in the course of its movement and operative,to cause reversal in the direction of movement eflected by said poweractuated means. rate changing mechanism disposed to be actuated by saidreversing mechanism and operative thereby to cause a change in the rateof movement eflected by said power actuated means, and selectivelyoperable means adapted to render said rate changing mechanismnon-responsive to said reversing mechanism, whereby reversal may beeffected selectively to provide either one of two rates of movement.

8. In a control systemior amovable machine tool member, the combinationwith hydraulically rate changing control valve selectively operable inresponse to operation of said reversing valve and effective to controlthe rate at which reverse movement occurs, and control means selectivelyoperable to render said rate changing control valve non-responsive tooperation of said reversing valve.

9. In a machine tool having a reciprocating supporting member, thecombination with power actuated means for movingsaid member, of ahydraulic control system for said power actuated means including areversing valve disposedto be moved by said member in the course of itstravel and operative to effect reversalin the direction of movement ofsaid member, a rate changing valve movement of said member upon reversalthereof,

ternatively at feed rate or at rapid traverse rate,

of a plurality of independently operable controland a manuallyactuatable valve arranged to render said rate changing valveinoperative,

-ers associated respectively plungers and'operative when -'positions,and a pair of whereby reversal may be caused to occur at either the sameor a diflerent rate selectively.

10. In a machine tool having a movable member, the combination withtransmission mecha nism including direction reversing andmotioninterrupting means and rate changing means, of

a reversing and disconnecting mechanism and rapid traverse drivemechanism, a control system responsive to movement of said reversingmechanism and functioning to render said rapid traverse drive mechanisminoperative whenever said reversing mechanism is in disconnectingposition. 12. In an automatic reversing control system for a movableelement or a machine tool. a reversing valve responsive to movement ofsaid machine tool element and operative to eilect reversal in itsdirection of movement, a rapid traverse valve responsive to movement ofsaid reversing valve and operative to eflect movement or said element atrapid traverse rate, and control means selectively operable to rendersaid rapid traverse valve non-responsive to movement of said reversingvalve.

13. In a machine tool having a movable ele- .ment and driving mechanismtherefor including a reverser, the combination with a reversing valveresponsive to movement of said machine element and operative to actuatesaid reverser for eflecting reversal in the direction of movement obsaidelement, a rapid traverse valve responsive to movement of said reversingvalve and operative to eflect movement of said element at rapid traverserate, a valve associated with said reverser and operative to preventmovement of said rapid traverse valve by said reverser valve prior tocompletion of a reversing movement, and a manually actuatable valveselectively operable to prevent actuation 0! said rapid traverse valveby said reversing valve at any time.

14. In a control system for a movable member, the combination with poweroperated means for moving said'member, of trip dogs carried by saidmember, apair 01' dog actuated plungers respectively operable whenengaged by dogs on said member to effect reversal in the direction andsimultaneous change in-the rate of movement of said member at 'oppodteends of its path of movement respectively, and a pair of auxiliaryplungwith said reversing engaged by dogs on said member at the time oi!reversal to render said reversing plungers inoperative to change therate of movement oi said member upon reversal thereof.

15. In a machine tool control syste ,the coma machine automatic reversalin the direction of movement of said member and responsive respectivelyin movement thereof to predetermined terminal control members associatedwith said reversing plungers andselectively engageable for actuationthereby to control the rate at which reverse movement of saidmemberoccurs.

16. In a machine tool having a movable member and driving means for saidmember including a direction reverser, and a rate changer, control meansresponsive to movement of said member and operative to actuate saidreverser for effecting reversal in the direction of movement of saidmember, control means responsive to movement of said reverserjto eachreversing position respectively and operative to actuate said ratechanger for effecting change-in the rate of movement of said member inthe reverse direction, and means for rendering inoperative each of saidrate changing control means selectively, whereby automatic reversal maybe caused to occur at either rate at either end of the course of travelof said member.

17. In a machine tool having a movable member, a power transmissionmechanism for moving said member including rate changing and reversingmechanism, hydraulic control apparatus for controlling said transmissionmechanism including a reversing valve adapted to be moved in oppositedirections respectively at the ends of the path of travel of saidmovable member and operative to control said reversing mechanism, a ratechanging valve operative to control said rate changing mechanism, a pairof control conduits leading from said reversing valve to said ratechanging valve and operative respectively to actuate said ratechangingvalveupon movement of mechanism,

' traverse valve operative admit fluid pressure from said reversingvalve to its positions, and a selective control valve in each of saidcontrol conduits said control valves being operative respectively tocontrol the actuation oi said rate changing valve upon reversal of saidmember at the opposite end of its travel, whereby said member may bereversed automatically into movement in reverse direction at apredetermined rate at'either end 01' its path oi! travel.

. 18. In a machine tool havlnfl a movable member and driving mechanismfor said member including rate changing. and direction reversing thecombination with a source oi pressure fluid and a reversing valveresponsive to movement of said member and operative to actuate saidreverser for effecting reversal in the direction of movement of saidmember, of a rapid to control said rate changing mechanism to eiIectmovement of said member at feed rate or at rapid traverse rate, a pairof control conduits leading from said reversing valve to said rapidtraverse valve, a valve associated. with said reverser and operativeupon movement thereof said reversing valve into a corresponding one oisaid control conduits. and a manually actuatable valve connected in eachof said conduits and selectively operableto admit said pressure fluidinto said rapid traverse valveior actuating it to eiiect reversal intomovement at rapid traverse rate, whereby reversal in the direction ofmovement of said movable member may be effected at either rate at eitherend of its course of travel in accordance with the adjustment of saidmanually actuatable valves.

19. In a machine tool, the combination with a movable suDNfl and drivingapparatus for actuating said support including rapid traverse ratedriving means and reversing and disconnecting means, of automaticcontrol mechanism for controlling the movement of said supportcomprising trip means for eiiecting automatic reversal and simultaneouschange in rate of movement of said respective reversing to eachreversing position to driving means inoperative whenever said selectormeans is in stop position, whereby engagement of said selector whilebeing rate is prevented.

21. A machine tool comprising a movable support, transmission mechanismfor moving said support including means for eiieoting support driven atrapid traverse trol valve, a hydraulically actuated rate changingmechanism connected to and arranged to be'operated in response tooperation of said reversing mechanism in effecting reversal of movement01' said machine element in either direction, and rate controllingvalves in the connec tion between said reversing mechanism and said ratechanging mechanism and operative selectively to permit or preventoperation of said said rate changing mechanism by said reversingmechanism, whereby said machine tool element may be reversed at eitherend or its stroke of travel either at the same'rate or at a difl'erentrate selectively.

25. In a machine tool reversing control mechanism, the combination withpower means for moving a machine tool element, of a hydraulic controlvalve operable'to eilect change in the movement in either direction,means for driving said transmission mechanism at either feed rate orrapid traverse rate selectively, control means for reversing andchanging the rate of movement of said support, said control means beingoperative to stop said support, and interlocking means associated withsaid control means and operative to efl'ect disengagement of the rapidtraverse driving means from said transmission mechanism upon stoppingsaid support, whereby when said support is started it will move at feedrate unless said control means is actuated to change the rate to rapidtraverse.

22. In a machine tool having a base and a supporting element movablymounted on said base, 2

means for moving said supporting element selectively in either directionat either feed rate or 'rapid traverse rate, a hydraulic control systemfor said element moving means including a hydraulically actuatedreversing valve adapted to be moved in either direction from a centralneutral position to effect movement of said supporting element in acorresponding direction, a rate changing valve adapted to be moved byfluid.

pressure under the control of said reversing valve to eflect movement ofsaid supporting element at rapid traverse rate subsequent to a reversingoperation and simultaneously to eflect a hydraulic connectionfunctioning to return said reversing valve to its neutral position,means selectively operable to render said rate changing valvenonresponsive to said reversing valve for eflecting reverse movement atfeed rate, and an auxiliary neutralizing valve operative when said ratechanging valve is non-responsive to eiIect neutralization of saidreversing valve subsequent to a reversing operation.

23. In a control system for a movable machine tool element, ahydraulically actuated control valve adapted to efiect operation of saidelement in either direction selectively, means for applying hydraulicpressure to move said control valve in the one or the other directionfrom a central neutral position to select the direction of operation ofsaid machine element, and two neutralizing valves associatedrespectively with the means for applying pressure to said control valveand operative subsequent to a direction selecting movement to applyequal pressures tending to move said control valve in each directionthereby neutralizing it for returnto its neutral position.

2%. In a control system for regulating the movement of a machine toolelement, a control valve responsive to'movement of said element, a

rate of movement oi'said element, a dog actuated hydraulic control valveoperable to eflect reversal in the direction of movement of said elementand connected to actuate said rate changing control valvesimultaneously, and means selectively operable to disconnect said ratechanging control valve from said reversing valve.

26. In a machine tool transmission and control mechanism, means formoving'a machine tool element in either direction, means for 'drivingsaid element moving means at either feed rate or rapid. traverse rate,direction controlling means associated with said element moving meansand operative to stop said element or to start it for movement in eitherdirection selectively, rate controlling means associated with saiddriving means and operative to control the rate of driving said elementmoving means, and means interlocking said direction controlling meansand said rate controlling means in such manner that when said directioncontrolling means is adjusted to stop said element said rate controllingmeans is automatically adjusted to cause driving of said element movingmeans to occur at feed rate.

27. In a machine tool, a movable element, to provide power for movingsaid element at feed rate or at rapid traverse rate. reversing anddisconnecting mechanism connected to be driven by said power means atselected rate, and control means associated with said reversing anddisconnecting mechanism and operative to prevent said power means fromdriving said reversing mechanism at rapid traverse rate when it is indisconnecting position, whereby starting or reversing of said machineelement viated.

28. In a machine tool control system for selecting the direction andrate of movement of a machine element, a hydraulically actuatedreversing mechanism, a reversing valve adapted to at rapid traverse rateis obcontrol the operation of said reversing mechanism, valve meansassociated with said reversing mechanism and adapted to control the flowof pressure fluid into one or the other of two pressure conduits whensaid reversing mechanism is positioned to effect movement 01' said thedirection of movement 01' said member, a hy- I draulic control systemincluding a. reversing valve operable to energize said hydraulicreversing means at predetermined points in the path of movement of saidsupporting member, a rate changing valve selectively operable uponmovement of said reversing means to either of two reversing positions tochange the rate of movement of said member, and selectivelyv actuatablecontrol valves respectively associated with each 01' said reversingpositions of said reversing means and selectively operative to preventoperation of said rate changing valve, whereby reversal may be caused toeflect reverse movementalternatively at either of two rates at either ofsaid reversing positions.

JOSEPH B. ARMITAGE. ORRIN W. BARKER.

